To automatically controlling anesthesia during surgical operations, researchers have created a new technique. The new system detects the hypnotic state of the patient at all times and supplies the most appropriate dose of anesthetic.

Juan Albino Méndez, lead author of the study and a researcher in the Anesthesia Control Group at the University of La Laguna (ULL), tells SINC," This is an efficient control technique which regulates anesthesia in operating theatres by computer, with the aim of adapting the dose of the drug administered according to the individual characteristics of each patient."

The new system, which has been published in Computer Methods in Biomechanics and Biomedical Engineering, keeps the patient in the desired hypnotic state throughout the operation.

Patient''s encephalogram (EEG) and bispectral index (BIS), are recorded by the system using sensors and a monitor, a parameter without units that measures hypnotic state and relates this to the patient''s level of consciousness.

This research focuses on the BIS region involved in general anesthesia, between 40 and 60. The BIS value fluctuates between 100 (maximum possible state of alertness) and 0 (lack of cortical electrical activity, the state of deepest unconsciousness).

The data are processed by a computer with specific control software, which can control the pump that injects the anesthetic in order to regulate the amount given. The IT application is based on adaptive PID (Proportional Integral Derivative) algorithms, a control-loop feedback mechanism that automatically controls the right dose according to the measured and desired values.

In order to validate the technique, the researchers tested it on 15 volunteer patients, aged between 30 and 60, at the University Hospital of the Canary Islands. Albino Méndez says," The first results obtained, both in surgery and in the simulations, show that the system operates very satisfactorily, and has surgical applications with well-founded expectations of success." (With Input from Agencies)